Odpowiedź:
[tex]b)\\\\(4-5x)(2+x)=-(4+5x^2)\\\\8+4x-10x-5x^2=-4-5x^2\\\\8-6x-5x^2=-4-5x^2\\\\-6x-5x^2+5x^2=-4-8\\\\-6x=-12\ \ |:(-6)\\\\x=2\\\\\\c)\\\\4x^2-2x=(2x+1)(2x-3)\\\\4x^2-2x=4x^2-6x+2x-3\\\\4x^2-2x=4x^2-4x-3\\\\4x^2-2x-4x^2+4x=-3\\\\-2x+4x=-3\\\\2x=-3\ \ |:2\\\\x=-\frac{3}{2}\\\\x=-1\frac{1}{2}[/tex]
